Subminiature potentiometer



Aug. 24, 1954 J. M. RILEY 2,687,463 SUBMINIATURE POTENTIOMETER Filed Sept. 10, 1953 INVENTOR. /an WW6 BY w. FM

e g/emf Patented Aug. 24, 1954 UNITED STATES PATENT OFFICE 2,687,463 SUBMINIATUR-E POTENTIOMETER John M. Riley, Smyrna,

assignments, to Chane corporated, a corporation of Delaware Application September 10, 1953, Serial No.

7 Claims.

This invention relates to electrical components With electrical able transformers and the like.

Of the miniature potentiometers now available,

shock, acceleration, vibration and extreme temperature conditions.

Another object of this invention is a potentiometer which other injurious media.

A further object of this invention is to a potentiometer of the and compact in its design with the ability of effective and efiicient operation while maintaining the ability to handle the loads to which it may be subjected under various extreme conditions.

A still further object of this invention is to Ga., assignor, by mesne e Vought Aircraft, In-

provide a potentiometer for easy adjustment of either voltage or resistance of fiber glass, having good insulating qualities.

relationship open-end box-like structure.

they form an The end caps l8 provide orifice 2| through the A composition resistance element 20 is applied to the inner major surface of one of the housing members as shown on member I4 in 2. While the resistance composition can be made cient solvent or thinner to bring the compound to a painting or spraying consistency. It will be understood that changes in resistance value can be readily obtained by changing the ratio of the carbon to binder material and the formula is accordingly prepared for the particular resistance value desired. Such composition resistor elements provide a high degree of sensitivity and are little affected by temperature changes. Two terminals 36 and 32, in contact with the ends of composition element 20, project through the housing l4 to which they are firmly affixed as by riveting, and provide exterior terminal contacts.

A conductor element 22 is mounted on the inner major surface of dielectric channel member l2. The conductor 22 is made of a highly-sensitive non-corrosive material, num, phosphor bronze or copper. Two terminals. 34 and 36 having contact with conductor element 22 project through they are firmly affixed as by riveting to provide exterior terminal contacts. Terminals 34 and 33 also serve to hold conductor element 22 inplace on the inner surface of channel member |2.

The end caps l6 and I8 are so constructed as to effectively position the two channel members =|2 and I4 which make up the container 10.; A screw 24 threaded over its entire shanklengthis axially mounted in housing It), passing through the apertures 2| in end caps l6 and 8.- The head of screw 24 rests in recess IQ of bass H of one end cap while the other end of screw 24 extends through aperture 2| and into recess IQ of the other end ca where it is held in place by setting a collar 26 on the screw and burring the threads, so as to join both the screw 24 and the collar 26 together, thus holding the housing elements in position within the confines of the flanges on end caps l6 and is protected from outside interference by means of a dust cap 28 which has a friction fit over boss A carrier or traveler 38, preferably constructed of a melanin fibre, is provided, having a main body portion 39 and cylindrical bosses 40 and 4| extending on either side of main body portion.-

The height dimension of the main body portion 39 is such as to provide a sliding fit with the internal surfaces of the flanges of channel members l2 and I4, thus preventing the carrier38' from turning Within the housing, while the width of carrier 38 is less than the distance between the conductor 22 and the resistance element 20. Carrier 38 is drilled and continuously threaded through boss 43, main body 39 and boss 4|., A- wiper element 44 composed of material having high conductance qualities such as phosphor bronze is mounted on boss 40 and positioned thereon by a lock ring 45 fitting in groove 42' of boss 40. The wiper 44 has arcuately bent side flanges 46 and 41 which present a sliding arcuate surface to the resistance element and conductor 22. The side flanges also serve to hold wiper 44 in position relative to the main body portion 39 of carrier 3-8. It will be understood that carrier 38 is threaded onto screw 24 prior to the assembly of the screw to the housing elements l2, l4 and end caps l6, l8 as explained in the preceding paragraph. The bosses 40 and 4| of carrier 38 act as sto members when they abut end cap 16 or l8, thus limiting the movement of carrier 38 within the contacts 30, 34 near one end of the housing and contacts 32, 36 at the other end of the housing.

The head 48 of the adjusting screw 24 is slotted as at 53 to permit adjustment by means of a screwdriver.

The adjustment of the potentiometer is brought about by rotating the head 48 of the adjusting screw 24 relative to the adjustment desired. When head 48 is rOtated the jackscrew effectof such as silver, gold, plati'e.

channel member |2 to .which I8. The collar 26 screw 24 moves carrier 38 and wiper 44 along the length of the adjusting screw 24, wiper 44 being in contact with both the composition resistor 20 and the conductor plate 22. The desired resistance setting may thus be obtained on test bench adjustment before the potentiometer is put into use in an electrical circuit.

It will be understood that the. wo contacts 34 and 36 to the conductor 22-, are provided for multiple circuit connections, if desired. :While only one embodiment of the invention has been shown in the accompanying drawings, it will be evident that various modifications are possible in the arrangement and construction of these electricalcomponents without departing from the scope of .the invention.

Nowhavingdescribed and explained the nature of this invention 1 claim:

1. An adjustable potentiometer for miniaturized equipment comprising; two mating channel-shaped members. forming -a.,.parallelep i-ped housing, end caps adapted tofit over 'the j'ends, of said channels, an axially mounted screw e tending through said end caps having an adjust ing head extending externally of said'housing and a collar fixedly mated to the end of said screw opposite said head, a traveler'adjustably mounted on said screw within-said-;h0using;,;a composition resistance-element mounted on an interior wallof one of said channel members, a; conductor plate mounted on an interior wall of said channel member opposite said resistance. element, a wiper element mounted on said traveler; having electrical contact with said compositionresistance element and said 'conductor'plate, ands terminals having individual contact with said resistance element and said conductor: plate and extending externally 'of'saidhousing} 2. A variable potentiometer "comprising. a parallelepiped shaped housing, "a composition resistance element composed of a carbon com: pound painted on an internal wall of'said h'o'using, a conductor plate mounted onthe'internal' surface of the opposite wall of said housing, ter-" minal elements contacting each of said're'sis'tance" element and said conductor plate and extending externally of said housing; a"traveler ;mounted Within said housing having-ameans of adjustment outside of said housing, and a wiper carried-by said traveler and having sliding" contact-with said composition element and 'with said conductor'.=---- position and having 3. A miniature variable potentiometer com prising, a pair of mating dielectric channel rhem bers forming a housing, a pair offiang'e'dFend caps fitting over the ends of said mating channel members, a screwjack axially mounted in said housing through said end caps to hold" said channel members and said end caps in assembled an external adjustment means, a traveler mounted onsaid screwjack having a sliding fit with two walls oijsaid housing, a carbon composition resistance elementapplied to one internal wall of said housing, a conductor element mounted on an internal wall of said housing in opposed relationship to said resistance element, wiper means fixedly mounted onsaid traveler and contacting said resistance element and said conductor element, and terminals'fiii contact with said resistance element ands ai dj conductor element and extending exteriorly qf. said housing. 4

4. A miniature variable potentiometenco prising, a pair of mating dielectric channel ers fir awman; re re -flan es en a carbon compotoluene in comtravel of said traveler by abutment against said end caps.

6. A variable miniature potentiometer comprising said resistance element and said conductor to provide contact points exteriorly of said housing, cover the ends of the resistance value.

7. The method of making a variable miniature potentiometer comprising the following steps: first, painting an interior surface of a channel ing in a position where said wiper contacts both said resistance composition and said conductor element.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,371,049 Oler Mar. 8, 1921 2,178,241 Rubinstein Oct. 31, 1939 2,229,072 Green Jan. 21, 1941 

